1. Field of the Invention
The present invention relates to a driving force receiving member, a shaft coupling, a toner image bearing member, a process cartridge and an electrophotographic image forming apparatus.
The xe2x80x9celectrophotographic image forming apparatusxe2x80x9d refers to an apparatus for forming an image on a recording medium by using an electrophotographic image forming system. For example, the electrophotographic image forming apparatus may be an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer or an LED printer), an electrophotographic facsimile or an electrophotographic word processor.
The xe2x80x9cprocess cartridgexe2x80x9d incorporates therein an electrophotographic photosensitive member, a charge means and a cleaning means, as a cartridge unit which can be detachably mounted to a main body of an electrophotographic image forming apparatus or incorporates therein an electrophotographic photosensitive member and a cleaning means, as a cartridge unit which can be detachably mounted to a body of an electrophotographic image forming apparatus. Since such a process cartridge can be mounted to or dismounted from the image forming apparatus by an operator himself, the maintenance of the image forming apparatus can easily be performed.
2. Related Background Art
In electrophotographic image forming apparatus using an electrophotographic image forming system, an electrophotographic photosensitive member uniformly charged by a charge means is selectively exposed in accordance with image information to form a latent image. The latent image is developed by a developing means with toner to form a toner image. Thereafter, the toner image formed on the electrophotographic photosensitive member is transferred, by a transfer means, onto a recording medium. In this way, image formation is performed.
In such image forming apparatuses using an electrophotographic image forming process, a process cartridge incorporating therein the electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member as a cartridge unit, which can detachably mounted to a body of the image forming apparatus, has been used. By using such a process cartridge, since the maintenance of the image forming apparatus can be performed by the operator himself without any expert, the operability can be improved considerably. Thus, such a process cartridge has widely been used in the image forming apparatus.
Regarding such a process cartridge, the body of the image forming apparatus is provided with a drive source, and a driving force is transmitted from the drive source to the process cartridge through a driving force transmitting means.
For example, an example of a method for rotatingly driving an electrophotographic photosensitive drum is disclosed in Japanese Patent Laid-Open Application No. 62-65049 (1987). According to this method, a pin secured to a side surface of a gear provided within the main body of the image forming apparatus is fitted into a recessed portion formed in a gear provided on the photosensitive drum, thereby rotating the photosensitive drum.
According to another method disclosed in Japanese Patent Laid-Open Application No. 63-4252 (1988), a helical gear provided within the body of the image forming apparatus is engaged by a helical gear provided on the photosensitive drum, thereby rotating the photosensitive drum.
These techniques are effective to transmit a rotational force to the photosensitive drum. The present invention relates to an improvement of such techniques.
An object of the present invention is to provide a driving force receiving member, a shaft coupling, a toner image bearing member, a process cartridge and an electrophotographic image forming apparatus, in which rotation accuracy is improved.
Another object of the present invention is to provide a driving force receiving member, a shaft coupling, a toner image bearing member, a process cartridge and an electrophotographic image forming apparatus, in which a driving force can be transmitted positively.
A further object of the present invention is to provide a driving force receiving member, a shaft coupling, a toner image bearing member, a process cartridge and an electrophotographic image forming apparatus, in which drive input accuracy and rotation accuracy are improved to obtain stable high quality.
The other object of the present invention is to provide a driving force receiving member, a shaft coupling, a toner image bearing member, a process cartridge and an electrophotographic image forming apparatus, in which a driving force is transmitted by using protruded portions having acute inclined surfaces with respect to a rotational direction, and surfaces contacted by such inclined surfaces.